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for a quote. CUSTOMER SITUATION:El Paso Corporation constructed the Ruby Pipeline, a 680-mile, 42-inch natural gas line spanning from Opal, Wyoming, to Malin, Oregon. Spiral weld and straight seam pipe were used, and the line was designed under the Alternative Maximum Allowable Operating Pressure (MAOP) rule (80% Specified Minimum Yield Strength design). As part of the Alternative MAOP rule, the United States Pipeline and Hazardous Materials Safety Administration (PHMSA) instructed operators to perform a high resolution caliper inspection to address the threat of low yield strength pipe. Pipe expansion could result from hydrostatic testing if the steel has lower than specified strength properties. PHMSA called for operators to identify all expansions greater than 0.6% for 42-inch pipe, dents greater than 2% and dents that affect a weld. The tool specifications required multi-finger sensors that contact the pipe inside diameter (ID) and have an accuracy of +/- 1% or less. Ruby Pipeline was required to report all findings to PHMSA.

TDW SOLUTION:El Paso Corporation contracted TDW to conduct inspections on 15 of the pipeline’s 30 total segments, for a total of 341 miles. TDW converted a standard two-body deformation (DEF) tool into a single body tool without sacrificing the high resolution capabilities for locating and characterizing dents, ovalities and expansions. The multi-channel tool needed to run post-hydrotest but pre-gas, so TDW coordinated with a contractor to get appropriate air compression to run the tool at a constant speed (avoiding starts and stops). TDW provided tool results and graphs of all expanded joints, as well as upstream and downstream joints for each identified expansion. Once data analysis was complete, TDW conducted non-destructive evaluation (NDE) services. Field measurements were used to calculate an inner diameter of the pipe, which was then compared to the ID reported by the inspection tool to validate tool accuracy. Upon completion of the inspections, no indications of low yield steel were identified within the pipeline.

CUSTOMER BENEFIT: The inspection work performed by TDW on the Ruby Pipeline is a good example of how inline inspection technologies (such as deformation) that have traditionally been used to identify restrictions or damage from external forces can also be used to locate and size expansions from internal forces (such as hydrotesting). If pipe material concerns exist, even in newly constructed lines, use of an inspection tool and subsequent data analysis can be instrumental in identifying potential trouble spots before they become problematic.

TDW converted a standard two-body deformation (DEF) tool into a single body tool without sacrificing the high resolution capabilities for locating and

characterizing dents, ovalities and expansions.

TDW provided tool results and graphs of all expanded joints as well as

upstream and downstream joints for each identified expansion.

Field measurements were used to calculate an inner diameter of the pipe,

which was then compared to the ID reported by the inspection tool to

validate tool accuracy.